Computer numerically controlled (CNC) machines for working substrates, for example milling machines, drill presses, axial boring machines, lathes and the like, typically comprise a tool configured for motion relative to the substrate. The tool may be rotary (e.g. a drill bit) or non-rotary (e.g. a lathe chisel). The substrates may comprise metal, wood, plastic or ceramic. These machines are equipped with some form of electronic control for automated operation of the machine to form a part or work piece from the substrate.
In some machines, the electronic controls are capable of sensing a current draw of the motor connected to the rotary substrate working tool in order to issue an alarm and stop the tool in the event that an increase in current draw occurs, signifying an increase in torque associated with a jam that could potentially damage the tool or the machine.
However, the machines and supplied controls often suffer from one or more of the following problems: the set points for speed and torque are not readily user adjustable; the set points are not settable according to each individual part or work piece, but instead are settable for the machine globally; there is no ability to apply different set points at different locations on an individual work piece (for example, when the bit encounters a previously bored cross-hole of the work piece, leading to an expected change in torque); the machines are not pre-programmed to clear the jam and attempt to restart automatic operation; the machines are not programmed to account for expected increases in torque according to drill bit or tool wear over a monitored period of time; the machines are not programmed to issue an alarm or alert when a pre-determined amount of drill bit or tool wear has occurred. This results in increased tool wear, tool breakage and machine down-time.
There remains a need for improved electronically controlled machines for working substrates, particularly control hardware, software, systems and methods of operation of said machines, which address one or more of the above problems.